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E. Undervoltage Unit (Lower Unit)
NOTE: The moving contact is in closed position
to the left when deenergized.
1) Contact Gap Adjustments
a. L.H. (Normally Closed) Contact Adjustment
With the moving contact arm in the closed
position, against left-hand side of bridge,
screw the left-hand contact in to just touch
the moving contact (see neon light for indica-
tion) and then continue for more complete
turn.
b. R.H. (Normally Open) Contact Adjustment
With moving contact arm against the left
hand stationary contact screw the right-hand
stationary contact until it just touches the
moving contact. Then back the right-hand
contact out two-thirds of one turn to give
0.020 inch contact gap.
2) Sensitivity Adjustment
a. Apply voltage to terminals 4 & 7. connect the
brush lead of the adjustable resistor that is
located n the rear (second from the bottom)
to maximum. Adjust the spring so that con-
tacts make (to the left) at 40 volts. The con-
tact should open when unit is energized with
41 or more volts.
b. Relay is set for 53 volts. This is accom-
plished by lowering resistance value until
contacts make at 53 volts and open when
unit is energized when 54 or more volts. The
spring should not be used for this setting.
F. Indicating Contactor Switch (ICS)
Close the main relay contacts and pass sufficient dc
current through the trip circuit to close the contacts of
the ICS. This value of current should not be greater
than the particular ICS tap settings being used. The
indicator target should drop freely.
G. Telephone Relay
Energize the telephone relay circuit, terminals 10 and
3, with rated dc voltage. The telephone relay (X)
should operate positively. With an air gap of .003" –
.004" the contacts should close in 167 to 250 ms
when the telephone relay coil is shorted. this may be
done by manually closing the distance unit (Z) and
directional unit (D) contacts.
H. Compensator Check
Accuracy of the mutual impedance T of the compen-
sators is set within very close tolerances at factory
and should not be changed under normal conditions.
The mutual impedance of the compensators can be
checked with accurate instruments by the procedure
outlined below:
1. Set T
on the 15.8 tap
A
T
on the 5.1 tap.
A
2. Disconnect the L-leads of sections M
M
.
C
3. Pass 10 amperes ac current in terminal 9
and out of terminal 8.
4. Measure the compensator voltage with an
accurate high resistance voltmeter (5000
ohms/volt).
5. compensator A-voltage should be checked
between lead L
A
For T
= 15.8 the voltage measured should
A
be 158 volts ±3%.
6. Compensator C voltage should be checked
between lead LC and the front terminal of the
reactor (X
).
D
For T
= 5.1, the voltage should be 51 volts
C
(±3%).
7. For all other taps the compensator voltage is
IT ( 3%).
where I - relay current
T - tap setting.
10. RENEWAL PARTS
Repair work can be done most satisfactorily at the
factory. However, interchangeable parts can be fur-
nished to the customers who are equipped for doing
repair work. When ordering parts, always give the
complete nameplate data.
I.L. 41-748.1F
A
and terminal 5.
and
19
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